1. Field of the Invention
The present invention relates to a semiconductor device having an IGBT (Insulated Gate Bipolar Transistor), and more particularly to a power semiconductor device integrating an LDMOS (lateral double-diffused metal oxide semiconductor) device with a lateral IGBT, which is fully compatible with CMOS process employing bulk silicon substrate.
2. Description of the Prior Art
Controllers, memories, circuits of low-voltage operation and power devices of high-voltage operation have been largely integrated together to achieve a single-chip system. The power device, such as vertical double-diffusion metal-oxide-semiconductor (VDMOS), insulated gate bipolar transistor (IGBT) or lateral diffusion MOS (LDMOS), has been employed to increase power switching efficiency and decrease the loss of energy resources. It is often required that the switching transistors withstand high breakdown voltages and operate at a low on-resistance.
Double diffuse drain (DDD) technology has been extensively applied to the source/drain (S/D) in order to provide a higher breakdown voltage. The DDD structure suppresses the hot electron effect caused by the short channel of the MOS transistor to further avoid electrical breakdown of the source/drain under high operational voltages. The LDMOS transistors are particularly prevalent because they can operate with a high efficiency and their planar structure allows for easy integration on a semiconductor die with other circuitry.
The IGBT is a power semiconductor device having both a high speed switching property of a power MOSFET and a high output property of a bipolar transistor. For this reason, the IGBT devices are frequently used in the field of power electronics, such as an inverter, a switching power supply, or the like. Among the IGBTs, a lateral IGBT draws attention, since it is suitable for a high degree of integration level. Typically, the lateral IGBT is formed, using an SOI substrate, which requires extra masks and is thus more expensive.
It would be desirable in this industry to provide a power semiconductor device that integrates LDMOS with a lateral IGBT, which is CMOS compatible and employs bulk silicon substrate.